MCP Server

Claude Synergy includes an 11-tool MCP server that runs over stdio. Any MCP-compatible harness — Claude Code, Cline, Cursor, or custom Agent SDK agents — can query the changelog corpus in real time.

Wiring

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "claude-synergy": {
      "command": "claude-synergy-mcp",
      "env": {
        "HK_DB": "/path/to/data/claude-synergy.db"
      }
    }
  }
}

Claude Code

Add to your project’s .mcp.json:

{
  "mcpServers": {
    "claude-synergy": {
      "command": "claude-synergy-mcp",
      "args": [],
      "env": {
        "HK_DB": "/path/to/data/claude-synergy.db"
      }
    }
  }
}

Programmatic (Agent SDK)

import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';

const transport = new StdioClientTransport({
  command: 'claude-synergy-mcp',
  env: { HK_DB: '/path/to/data/claude-synergy.db' },
});

Tools

search

Full-text search across all change bullets.

Parameter	Type	Required	Description
query	string	yes	FTS5 search query
product	string	no	Limit to one product
since	string	no	YYYY-MM-DD lower bound
until	string	no	YYYY-MM-DD upper bound — new in v1.1
kind	string	no	added, fixed, breaking, etc.
limit	number	no	Max results (default: 20)

lookup_entity

Find when a specific entity (env var, slash command, model ID, CVE) was introduced or changed.

Parameter	Type	Required	Description
entity_type	string	yes	env_var, slash_command, model_id, cve, etc.
value	string	yes	The entity value to look up

latest_releases

Recent releases across all or one product.

Parameter	Type	Required	Description
product	string	no	Limit to one product
since	string	no	YYYY-MM-DD lower bound — new in v1.1
limit	number	no	Max results (default: 20)

get_release

Get the full content of a specific release.

Parameter	Type	Required	Description
product	string	yes	Product name
version	string	yes	Release version

list_products

List all products in the database with release counts. No parameters.

top_entities

Most-mentioned entities of a given type.

Parameter	Type	Required	Description
entity_type	string	yes	Entity type to rank
limit	number	no	Max results (default: 30)

list_synergies

List all curated cross-product synergy documents.

Parameter	Type	Required	Description
product	string	no	Limit to synergies that involve this product — new in v1.1

read_synergy

Read a specific synergy document by slug.

Parameter	Type	Required	Description
slug	string	yes	Synergy document slug (e.g. 01-skill-portability)

get_changes_since (new in v1.1)

Changes in a time window, grouped by product+version. Backs the hk diff CLI command.

Parameter	Type	Required	Description
since	string	yes	ISO date (YYYY-MM-DD), full ISO 8601, or relative (7d/2w/3m/1y)
until	string	no	Upper bound — same formats
product	string	no	Limit to one product
kind	string	no	Filter: added, fixed, breaking, deprecated, etc.
limit	number	no	Max total change rows (default: 200)

Example call:

{
  "name": "get_changes_since",
  "arguments": { "since": "2026-05-15", "product": "claude-code" }
}

Returns a ChangesSinceResult[] — same JSON shape hk diff --json emits: groups of {product, version, released_at, changes: [{kind, text}]}.

Note on date formats: Relative forms like 7d resolve to ISO at the CLI boundary. The MCP tool accepts the same forms, but they are passed through to the query layer — pass ISO YYYY-MM-DD for maximum portability across MCP hosts.

search_breaking_changes (new in v1.1)

Flat list of breaking changes — no search term required. Backs the hk breaking CLI command.

Parameter	Type	Required	Description
product	string	no	Limit to one product
since	string	no	YYYY-MM-DD lower bound
until	string	no	YYYY-MM-DD upper bound
limit	number	no	Max results (default: 50)

Example call:

{
  "name": "search_breaking_changes",
  "arguments": { "since": "2026-04-01", "limit": 20 }
}

compare_versions (new in v1.1)

All changes between two versions of one product. Useful for migration planning when you know the exact versions you’re upgrading between. The interval is exclusive at from_version, inclusive at to_version — i.e. it returns everything that changed after you were on from_version, up to and including to_version.

Parameter	Type	Required	Description
product	string	yes	Product slug
from_version	string	yes	Start version (exclusive — not included in results)
to_version	string	yes	End version (inclusive — included in results)

Example call:

{
  "name": "compare_versions",
  "arguments": {
    "product": "anthropic-sdk-typescript",
    "from_version": "0.94.0",
    "to_version": "0.95.1"
  }
}

Returns every change recorded across (0.94.0, 0.95.1] for anthropic-sdk-typescript, in the same ChangesSinceResult[] shape — grouped by release version. A single call replaces N+1 get_release lookups when planning an upgrade.

Safety properties

• No network calls — the MCP server reads only from the local SQLite database. No HTTP, no DNS, no egress.
• No code execution — accepts JSON-RPC queries, returns structured JSON results. Never executes user input.
• Structured errors only — all exceptions are caught and returned as McpError with error code and message. Stack traces are never exposed.
• Timeout protection — every query has a 30-second timeout guard. Hung providers cannot block the server.
• Graceful shutdown — handles SIGINT/SIGTERM and server.onclose for clean DB handle release.

Use patterns

Agent self-awareness

An MCP-connected agent can discover what its harness supports:

“What slash commands were added to Claude Code in the last 30 days?”

The agent calls search({ query: "slash command", product: "claude-code", since: "2026-04-22", kind: "added" }) and gets actionable results.

Cross-product planning

“Is there a way to use the same MCP server config across Claude Code and Cursor?”

The agent calls list_synergies(), finds the MCP portability synergy, reads it with read_synergy({ slug: "02-mcp-server-portability" }), and summarizes the compatibility matrix.

Migration guidance

“We’re upgrading from claude-3-haiku to claude-sonnet-4. What changed?”

The agent calls lookup_entity({ entity_type: "model_id", value: "claude-sonnet-4-20250514" }) and lookup_entity({ entity_type: "model_id", value: "claude-3-haiku-20240307" }) to compare timelines.

”What broke this week?”

“Did anything load-bearing break in the last week?”

The agent calls search_breaking_changes({ since: "<7 days ago>" }) and gets a flat list — no search term needed. For one product specifically, add { product: "claude-code" }.

Pin-to-pin upgrade brief

“We’re upgrading anthropic-sdk-typescript from 0.94.0 to 0.95.1. Give me the change brief.”

The agent calls compare_versions({ product: "anthropic-sdk-typescript", from_version: "0.94.0", to_version: "0.95.1" }) and summarizes the response into a migration checklist.